Re: [Q] normal practice if an engine fail @ t.o.?

From:         kls@ohare.Chicago.COM (Karl Swartz)
Organization: Chicago Software Works, Menlo Park, California
Date:         16 Jan 95 21:39:08 
References:   1
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Andrew Chuang <chuanga@iia.org> wrote:
>I have no doubt that the B747 can safely fly with three engines.
>However, what is the usual practice if a pilot experiences an engine
>failure at take-off on a four-engined aircraft?

About a year ago, I was on a United 747-422 that suffered a failure of
#2 during takeoff from San Francisco.  Shortly after we became airborne,
right about the time the landing gear is normally retracted, there were
a series of *very* loud bangs that seemed to shake the entire airframe.
They resembled the sound and feel of sitting directly over the landing
gear when they retract, except much louder, and I was sitting in the
*upper* cabin, second row behind the exit door.  This continued on for
10-15 seconds, with a bang every second or so, then we returned to what
seemed a perfectly normal departure from 1R, including a ten degree
turn to the right for separation from departures on 1L, then a normal
climb up to a few thousand feet.  We then began another turn to the
right, which normally would have put us on a heading over Tahoe and on
to Chicago.  Instead, we kept turning, and once on a course down San
Francisco Bay, the captain asked the flight attendants to prepare for
landing.

Later, I asked the pilots what had happened.  The captain started to
explain what I quickly realized was a compressor stall.  I was
surprised, as I thought a compressor stall would just produce one or
two loud bangs, not a whole series of them.  He said that it had been
a new experience for him as well, though this was by no means he first
compressor stall.

Our new aircraft was another 747-422 that had been stripped of all
supplies for cleaning, so there was plenty of time to chat while it
was being readied for our flight.  The captain said the first aircraft
had suffered a failed #2 engine somewhere across the Pacific (Manila
or Singapore, I think) and had been ferried back to SFO on only three
engines.  This was the first flight for the replacement engine, and it
was overheating almost from the start of the takeoff roll.

Apparently there was plenty of time for a rejected takeoff, but with
three good engines the pilots chose to complete the takeoff and return
immediately to SFO, avoiding any risk of a runway overrun, which would
have put us in the bay.

He also groused about all the paperwork they had to fill out to justify
an in-flight engine shutdown.  This seemed a little bit odd, especially 
when he noted that this was because it was a hit against their ETOPS
ratings.  He pointed out that while United's 747-400s obviosuly aren't
ETOPS, their PW4056 engines are in the same family as the PW4060 engines
used on United's 767-322(ER) fleet and thus any in-flight shutdowns are 
a strike against the reliability which must be maintained for ETOPS.

Of about 500 commercial flights in my life, this is the only one that
has had an in-flight mechanical problem, though I've had my share of
flights which had problems before they got to the runway, not to
mention a good number of weather delays or worse.  Some may think I'm
nuts (though probably not many readers of this group! ;-) ) but I
enjoyed the adventure, even with the nearly five hour delay it cost.
Amongst other things, it made up for my having missed the DC-8 flight
from OAK to SFO which I'd always wanted to fly on.  :-)

--
Karl Swartz	|INet	kls@ohare.chicago.com
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